“The book of Alma begins with a preface and ends with a summary statement in the last verse. In between there are a number of subdivisions set off by editorial statements. Mormon divided his abridgment of the book of Alma into (1) the record of Alma, which ends at 44:24 with ‘And thus ended the record of Alma’; (2) the record of Helaman, which is introduced by a preface between chapters 44 and 45 and which ends with an editorial statement in the last verse of chapter 62; and (3) the record of Shiblon, which is marked by statements at its beginning in 63:1 and its end at 63:11” (Tvedtnes, “Colophons,” 34).
In Mormon’s superscription preceding the war chapters in Alma, just prior to Alma 45, Mormon tells us that we are about to read several chapters that deal with wars and dissensions. President Ezra Taft Benson gave insight on these chapters: “From the Book of Mormon we learn how disciples of Christ live in times of war” (Teachings of Ezra Taft Benson, 59).
The superscription to Alma 45 was part of the ancient record translated by the Prophet Joseph Smith and dictated by him to his scribe (see also, for example, 2 Nephi, Mosiah 9, and Helaman).
The italicized words “Comprising chapters 45 through 62” were not part of the ancient record but were added later to printed editions of the Book of Mormon.